Quick connection between customized softap and sta

ABSTRACT

A method and apparatus for connecting a wireless station (STA) to an access point (AP). The STA broadcasts a probe request that includes a custom information element (IE), and receives probe responses from one or more APs in response to the probe request. The STA then identifies a target AP from the probe responses based at least in part on whether one or more of the received probe responses include the custom IE, and connects to the target AP. For example, the target AP may respond to the probe request by sending a probe response that includes the custom IE. The STA may thus identify a set of candidate APs based on one or more received probe responses that include the custom IE, and select the target AP from the set of candidate APs.

TECHNICAL FIELD

The present embodiments relate generally to wireless networks, andspecifically to reducing a connection time between a wireless stationand an access point.

BACKGROUND OF RELATED ART

A Wi-Fi network may be formed by one or more access points (APs) thatprovide a wireless communication channel or link with a number of clientdevices or stations (STAs). Establishing a Wi-Fi connection between anAP and a STA typically involves a number of steps that must be completed(in order) before the STA and AP can begin exchanging data with oneanother. First, the STA scans all available channels (e.g., bybroadcasting probe requests and/or listening for beacon frames) toidentify APs and/or other devices that are within Wi-Fi communicationrange. Each available AP may respond to a probe request by sending backa probe response containing basic service set (BSS) informationpertaining to that AP's network. Next, the STA selects one of the APs toconnect to, based on the associated network information. For example,the STA may select the AP with the highest signal strength. The STA thenauthenticates and associates with the selected AP. Finally, the STAperforms a 4-way handshake with the AP to generate dynamic keys forencrypting (and decrypting) data communicated between the devices.

Once connected, the STA may maintain a communication link with the AP bylistening for beacon frames periodically broadcast by the AP. If the STAdoes not receive a beacon frame from the AP within a given duration, theWi-Fi connection is lost and the STA may need to reconnect to the AP.However, the process for establishing (or re-establishing) a Wi-Ficonnection may take anywhere from 3 to 5 seconds, which may beundesirable for applications that require fast connection times.

SUMMARY

This Summary is provided to introduce in a simplified form a selectionof concepts that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tolimit the scope of the claimed subject matter.

A method and apparatus for reducing a connection time between a wirelessstation (STA) and an access point (AP) are disclosed. The STA broadcastsa probe request that includes a custom information element (IE). Forexample, the custom IE may be a vendor-specific IE that includes a mediaaccess control (MAC) address of the STA. In an example embodiment, theSTA may broadcast the probe request only on a predetermined channelassociated with a target AP. The STA receives probe responses from oneor more APs in response to the probe request, and identifies the targetAP from the probe responses based at least in part on the custom IE. TheAP then connects to the target AP.

The target AP may respond to the probe request by sending a proberesponse that includes the custom IE. Thus, the STA may identify thetarget AP by scanning the received probe responses for the custom IE.For example, the STA may identify a set of candidate APs based on one ormore received probe responses that include the custom IE. The STA maythen select the target AP from the set of candidate APs. In addition,the STA may initiate a timer upon broadcasting the probe request. If,upon expiration of the timer, none of the received probe responsesinclude the custom IE, the STA may rebroadcast the probe request withthe custom IE.

In an example embodiment, the STA may filter or ignore any proberesponses that do not include the custom IE. For example, to furtherreduce scanning time, the filtering of probe responses may be performedin firmware. The STA may also identify the target AP based at least inpart on beacon frames received from the target AP. For example, thetarget AP may broadcast beacon frames with the custom IE to helpmaintain and/or re-establish a connection with the STA.

The methods of operation disclosed herein enable a wireless device toquickly establish (and/or re-establish) a Wi-Fi connection with anotherwireless device. For example, in certain applications, a wireless devicemay intend to connect only to a particular target device and/or type ofdevice. By broadcasting probe requests with custom IEs, the wirelessdevice may quickly filter out unwanted probe responses (e.g., any proberesponses that do not contain a matching custom IE), thereby reducingthe number of potential connections the wireless device must analyzeduring the scanning process.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments are illustrated by way of example and are notintended to be limited by the figures of the accompanying drawings. Likenumbers reference like elements throughout the drawings andspecification.

FIG. 1 shows a communications system in accordance with exampleembodiments.

FIGS. 2A and 2B show example communications systems in which filteredscanning operations may be performed.

FIG. 3 shows an example timing diagram depicting a wireless connectionoperation with filtered scanning for access points (APs).

FIG. 4 shows an example timing diagram depicting a wireless connectionoperation with filtered re-scanning for APs.

FIG. 5 shows an example timing diagram depicting a wireless connectionoperation with filtered AP selection.

FIG. 6 shows a wireless station (STA) in accordance with exampleembodiments.

FIG. 7 shows a wireless AP in accordance with example embodiments.

FIG. 8 shows a flowchart depicting an example filtered scanningoperation.

FIG. 9 shows a flowchart depicting a more detailed example of a filteredscanning operation.

FIG. 10 shows a flowchart depicting an operation of an AP in accordancewith example embodiments.

DETAILED DESCRIPTION

The example embodiments are described below in the context of Wi-Fienabled devices for simplicity only. It is to be understood that theexample embodiments are equally applicable to other wireless networks(e.g., cellular networks, pico networks, femto networks, satellitenetworks), as well as for systems using signals of one or more wiredstandards or protocols (e.g., Ethernet and/or HomePlug/PLC standards).As used herein, the terms “wireless local area network (WLAN)” and“Wi-Fi” can include communications governed by the IEEE 802.11standards, Bluetooth®, HiperLAN (a set of wireless standards, comparableto the IEEE 802.11 standards, used primarily in Europe), and othertechnologies used in wireless communications. In addition, althoughdescribed herein in terms of exchanging data frames between wirelessdevices, the example embodiments may be applied to the exchange of anydata unit, packet, and/or frame between wireless devices.

In the following description, numerous specific details are set forthsuch as examples of specific components, circuits, and processes toprovide a thorough understanding of the present disclosure. The term“coupled” as used herein means connected directly to or connectedthrough one or more intervening components or circuits. Also, in thefollowing description and for purposes of explanation, specificnomenclature is set forth to provide a thorough understanding of thepresent embodiments. However, it will be apparent to one skilled in theart that these specific details may not be required to practice thepresent embodiments. Any of the signals provided over various busesdescribed herein may be time-multiplexed with other signals and providedover one or more common buses. Additionally, the interconnection betweencircuit elements or software blocks may be shown as buses or as singlesignal lines. Each of the buses may alternatively be a single signalline, and each of the single signal lines may alternatively be buses,and a single line or bus might represent any one or more of a myriad ofphysical or logical mechanisms for communication between components.Embodiments of this disclosure are not to be construed as limited tospecific examples described herein but rather to include within theirscope all embodiments defined by the appended claims.

FIG. 1 shows a communications system 100 in accordance with exampleembodiments. The system 100 is shown to include a wireless station (STA)110 and an access point (AP) 120. The STA 110 may be any suitablewireless device including, for example, a cell phone, personal digitalassistant (PDA), tablet device, laptop computer, or the like. The AP 120may be any suitable device that allows one or more wireless devices toconnect to a network (e.g., a LAN, WAN, MAN, and/or the Internet) via AP120 using Wi-Fi, Bluetooth, and/or any other suitable wirelesscommunication standards. In example embodiments, the AP 120 may be anysuitable wireless device (e.g., such as a wireless STA) acting as asoftware-enabled access point (“SoftAP”). Thus, the devices 110 and/or120 may also be referred to as a user equipment (UE), a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a wireless terminal, a remote terminal, ahandset, a user agent, a mobile client, a client, or some other suitableterminology.

For example embodiments, each of the devices 110 and 120 may include oneor more transceivers, one or more processing resources (e.g., processorsand/or ASICs), one or more memory resources, and a power source (e.g., abattery). The memory resources may include a non-transitorycomputer-readable medium (e.g., one or more nonvolatile memory elements,such as EPROM, EEPROM, Flash memory, a hard drive, etc.) that storesinstructions for performing operations described below with respect toFIGS. 8-10. The one or more transceivers may include Wi-Fi transceivers,Bluetooth transceivers, cellular transceivers, and/or other suitableradio frequency (RF) transceivers (not shown for simplicity) to transmitand receive wireless communication signals. Each transceiver maycommunicate with other wireless devices in distinct operating frequencybands and/or using distinct communication protocols. For example, theWi-Fi transceiver may communicate within a 2.4 GHz frequency band and/orwithin a 5 GHz frequency band in accordance with the IEEE 802.11specification. The cellular transceiver may communicate within variousRF frequency bands in accordance with a 4G Long Term Evolution (LTE)protocol described by the 3^(rd) Generation Partnership Project (3GPP)(e.g., between approximately 700 MHz and approximately 3.9 GHz) and/orin accordance with other cellular protocols (e.g., a Global System forMobile (GSM) communications protocol). In other embodiments, thetransceivers may be any technically feasible transceiver such as aZigBee transceiver described by the ZigBee specification, a WiGigtransceiver, and/or a HomePlug transceiver described in a specificationfrom the HomePlug Alliance.

In example embodiments, the communications system 100 is a Wi-Fi network(e.g., or wireless local area network (WLAN)) based on one or more IEEE802.11 protocols, although other wireless communications standards maybe employed by the system 100. Thus, to establish a Wi-Fi connectionbetween the STA 110 and the AP 120, the STA 110 may first scan one ormore wireless channels to identify the AP 120. In some instances, theSTA 110 may intend to connect only to the particular AP 120 (e.g., tothe exclusion of any other APs that may be in the vicinity of the STA110). Thus, in example embodiments, the STA 110 may perform a “filteredscan” for the desired AP 120.

The STA 110 may scan for the AP 120 by broadcasting a targeted proberequest 101, intended to cause a unique response by AP 120. For example,the targeted probe request 101 may include a custom information element(IE). The custom IE may be a vendor-specific information element (VSIE)containing information that is uniquely identifiable by the STA 110(e.g., such as a media access control (MAC) address of the STA 110, aMAC address of the AP 120, and/or other uniquely identifiableinformation). For example, a probe request associated with current IEEE802.11 specifications typically includes 150 Bytes of information,including several of the following information fields:

1. Service Set Identifier (SSID)

2. Supported Rates

3. Request Information

4. Extended Supported Rates

5. Direct Sequence Spread Spectrum (DSSS) Parameter Set

6. Supported Operating Classes

7. High Throughput (HT) Capabilities

8. 20/40 Basic Service Set (BSS) Coexistence

9. Extended Capabilities

10. SSID List

11. Channel Usage

12. Interworking

13. Mesh ID

14. Multi-Band

15. Directed Multi-Gigabit (DMG)

16. Multiple MAC Sublayers

17. Very High Throughput (VHT) Capabilities

18. Vendor-Specific Information Elements (VSIEs)

When the AP 120 receives the probe request 101, the AP 120 responds bysending a probe response that mirrors the information provided in theprobe request 101 intersected with the capabilities supported by the AP120. For example, if the probe request 101 contains a selected number(N) of the information fields listed above, the AP 120 may send atargeted probe response 102 including the selected number N of theabove-listed information fields when all N fields/capabilities aresupported by the AP 120. For some embodiments, the targeted proberesponse 102 may include a “matching” custom IE that is substantiallysimilar, if not identical, to the custom IE included in the proberequest 101. For example, the AP 120 may detect the custom IE in thereceived probe request 101 and mirror that custom IE (e.g., the MACaddress of the STA 110) in its probe response 102. In exampleembodiments, the AP 120 may respond to a probe request only if itdetects a particular custom IE. Still further, for some embodiments, theSTA 110 may filter (e.g., ignore) any received probe responses that donot contain the custom IE that was included in the targeted proberequest 101.

Upon receiving the targeted probe response 102, the STA 110 transmits anauthentication request 103 the AP 120. For example, the authenticationrequest 103 may trigger a low-level authentication mechanism describedby the IEEE 802.11 specification. The AP 120 subsequently responds tothe authentication request 103 by sending an authentication response 104back to the STA 110 to complete the authentication process. Onceauthenticated, the STA 110 may then send an association request 105 tothe AP 120. For example, the association request 105 may include one ormore requested capabilities (e.g., under the IEEE 802.11 specification)to be used for communications between the STA 110 and AP 120. If the AP120 can support the requested capabilities indicated in the associationrequest 105, the AP 120 may create an Association ID (AID) for the STA110 and send an association response 106 back to the STA 110.

Finally, the STA 110 and the AP 120 may perform a handshake 108 togenerate dynamic keys to be used for encrypting and decrypting datacommunications between the two devices. For example, the handshake 108may correspond to a 4-way handshake, as described in the IEEE 802.11specification, whereby the STA 110 and the AP 120 exchange ExtensibleAuthentication Protocol over LAN (EAPoL) frames with one another togenerate a pairwise transient key (PTK) to be used for data encryption(and decryption). The STA 110 is connected to the AP 120 once thehandshake 108 is completed. In example embodiments, the handshake 108may be performed in firmware (e.g., as opposed to being performed by thewpa_supplicant in the user space). For example, offloading the handshake108 to firmware may further reduce the connection time between the STA110 and the AP 120.

FIGS. 2A and 2B show example communication systems 200A and 200B,respectively, in which filtered scanning operations may be performed.With reference to FIG. 2A, the system 200A is shown to include a STA 210and a number of access points AP1-AP3 that “reside” (e.g., communicateor otherwise operate) on a wireless channel 220. For purposes ofdiscussion, with respect to the example of FIG. 2A, the STA 210 and AP3may be the STA 110 and AP 120, respectively, of FIG. 1. Thus, AP3 may bethe “target AP” (e.g., the intended target for wireless communicationswith the STA 210). Each of the remaining access points AP1 and AP2 maybe any suitable device that allows one or more wireless devices toconnect to a network (e.g., a LAN, WAN, MAN, and/or the Internet) viathat AP using Wi-Fi, Bluetooth, and/or any other suitable wirelesscommunication standards.

The STA 210 may initiate a filtered scan operation by broadcasting atargeted probe request (TPRQ) to all available APs residing on thewireless channel 220. In example embodiments, the STA 210 may broadcastthe targeted probe request TPRQ on a predetermined channel on which anintended target AP is known to reside. For example, AP3 may bepreconfigured to operate on wireless channel 220. Thus, to reducescanning time, the STA 210 may scan only the wireless channel 220 forthe target AP (e.g., as opposed to scanning all available channels underconventional Wi-Fi scanning operations). As described above, thetargeted probe request TPRQ may include a custom IE (e.g., storing theMAC address of the STA 210) which may be used to filter received proberesponses.

Each of the access points AP1-AP3 responds to the targeted probe requestTPRQ by sending a probe response that mirrors the information providedin the probe request intersected with the capabilities supported by thatAP. In the example of FIG. 2A, only AP3 may mirror the custom IE fieldof the targeted probe request TPRQ. For example, AP3 may bepreconfigured to associate with the particular STA 210 and/or aparticular class or type of device to which STA 210 belongs. Incontrast, AP1 and AP2 may be generic access points and/or may not bespecifically configured to associate with STA 210. Accordingly, AP3 maysend a targeted probe response (TPRS) with a custom IE that mirrors thecustom IE of the targeted probe request TPRQ, whereas the remainingaccess points AP1 and AP2 send non-targeted probe responses (e.g.,without the custom IE) back to the STA 210.

In example embodiments, the STA 210 may filter the received proberesponses based on the custom IE. For example, to reduce the duration ofthe scanning process, the STA 210 may ignore or filter any proberesponses that do not contain the custom IE (e.g., such as the proberesponses transmitted by AP1 and AP2). For example, during conventionalWi-Fi scanning operations, a STA typically analyzes its received proberesponses to select an access point (e.g., network) with the mostfavorable conditions and/or capabilities to connect to. By filteringincoming probe responses from non-targeted (e.g., “unwanted”) APs, theSTA 210 may significantly reduce the number of network connections to beanalyzed during the filtered scanning operation. This, in turn, maysubstantially reduce the time needed to establish a Wi-Fi connectionwith the target AP (e.g., AP3). For some embodiments, the filtering ofprobe responses may be performed in firmware (e.g., to further reducethe scanning time by limiting any delays that may be caused by thereception of such probe responses).

The STA 210 may identify AP3 as the target AP based on the custom IEincluded in the targeted probe response TPRS, and may subsequentlyestablish a Wi-Fi connection with AP3 based at least in part oninformation included in the probe response TPRS (e.g., as describedabove with respect to FIG. 1). For example, the STA 210 may send anauthentication request to AP3 upon determining that the custom IEincluded in the targeted probe response TPRS matches or mirrors thecustom IE included in the targeted probe request TPRQ. For someembodiments, the STA 210 may attempt to connect to the first AP fromwhich it receives a targeted probe response TPRS. For other embodiments,the STA 210 may wait a given duration before analyzing any receivedtargeted probe responses TPRSs (e.g., in case multiple APs send targetedprobe responses TPRSs).

After a Wi-Fi connection is established between AP3 and the STA 210, AP3may broadcast beacon frames containing the custom IE to enable the STA210 to maintain its connection to AP3. Furthermore, if the connectionbetween the STA 210 and AP3 is inadvertently lost (e.g., due to poorchannel conditions and/or movement of either of the devices), the beaconframes may also enable the STA 210 to quickly re-establish a connectionto AP3 (e.g., without having to actively scan for AP3 by broadcastingtargeted probe requests TPRQs). For example, during a passive scanningoperation, the STA 210 may again identify the target AP (e.g., AP3)based on whether the beacons include the custom IE. More specifically,the STA 210 may filter any incoming beacons that do not contain a customIE that matches or mirrors the custom IE of the STA 210 (e.g., includedin the targeted probe request TPRQ), while focusing only on receivedbeacons that contain the custom IE.

In an example embodiment, the STA 210 may initiate a scan timer uponbroadcasting the targeted probe request TPRQ. For example, in someinstances, the target AP (e.g., AP3) may fail to receive the targetedprobe request TPRQ sent by the STA 210 (e.g., due to interference and/orother channel conditions), or the STA 210 may fail to receive thetargeted probe response TPRS from the target AP. Accordingly, the STA210 may rebroadcast the targeted probe request TPRQ if it does notdetect any targeted probe responses TPRSs by the expiration of the scantimer. Thus, the scan timer may be used to ensure that the STA 210 doesnot dwell on the wireless channel 220 beyond a threshold duration oftime before rescanning the channel 220 for the target AP (e.g., tofurther reduce the duration of the filtered scanning operation). Thescan timer may also be used to set an overall duration for each scanningoperation. For example, the STA 210 may continue to listen for incomingprobe responses (e.g., even after receiving at least one targeted proberesponse TPRS) until expiration of the scan timer.

With reference to FIG. 2B, the communications system 200B is shown toinclude STA 210 and access points AP1-AP3 residing on wireless channel220. For purposes of discussion, with respect to the example of FIG. 2B,AP2 and AP3 may each correspond to AP 120 of FIG. 1. For example, AP2together with AP3 may form a wireless local area network (WLAN)according to the IEEE 802.11 family of standards. Thus, the STA 210 maytarget AP2 and/or AP3 to establish a wireless connection. The remainingaccess point AP1 may be any suitable device that allows one or morewireless devices to connect to a network (e.g., a LAN, WAN, MAN, and/orthe Internet) via the AP using Wi-Fi, Bluetooth, and/or any othersuitable wireless communication standards.

As described above, with respect to FIG. 2A, the STA 210 may initiate afiltered scan operation by broadcasting a targeted probe request TPRQ toall available APs residing on the wireless channel 220. The targetedprobe request TPRQ may include a custom IE (e.g., storing a MAC addressof the STA 210) which may be used to filter received probe responses. Inthe example of FIG. 2B, AP2 and AP3 may mirror the custom IE field ofthe targeted probe request TPRQ, whereas AP1 may not mirror the customIE. Accordingly, both AP2 and AP3 may send targeted probe responsesTPRSs with custom IEs that mirror the custom IE of the targeted proberequest TPRQ. In contrast, AP1 may send a non-targeted probe response(e.g., without the custom IE) back to the STA 210.

The STA 210 may filter or ignore the probe response from AP1 upondetermining that the probe response does not contain the custom IE. Asdescribed above, the filtering of incoming probe responses may beperformed in firmware of the STA 210. In example embodiments, the STA210 may listen for incoming probe requests for a given duration toensure that it receives the targeted probe responses TPRSs from both AP2and AP3. For example, the STA 210 may initiate a scan timer uponbroadcasting the targeted probe request TPRQ and continue listening forincoming probe requests until the scan timer expires.

Once the scan timer expires, the STA 210 may analyze any (and all)targeted probe responses TPRSs received during the scanning operation,and may select a particular AP to connect to (e.g., from a subset ofcandidate APs) based on the received probe responses. For example, theSTA 210 may select either AP2 or AP3 to connect to (e.g., AP1 is removedfrom consideration as a result of filtering) depending on thecapabilities and/or channel conditions associated with each accesspoint. If AP2 and AP3 are both viable candidates that offersubstantially similar capabilities, the STA 210 may select the AP withthe highest signal strength (e.g., as indicated by an RSSI value) toestablish a Wi-Fi connection with.

In example embodiments, after the STA 210 establishes a Wi-Fi connectionwith one of the access points AP2 or AP3, both AP2 and AP3 may broadcastbeacon frames containing the custom IE. For example, if STA 210initially establishes a Wi-Fi connection with AP2 and subsequently movesout of wireless range of AP2, but remains in range of AP3, the STA 210may quickly identify and establish a connection with AP3 based on thecustom IE included in its beacon frames. In this manner, the STA 210 mayquickly reconnect to the WLAN (e.g., formed by AP2 and AP3) withouthaving to initiate another active scanning operation.

FIG. 3 shows an example timing diagram 300 depicting a wirelessconnection operation with filtered scanning for APs. For purposes ofdiscussion herein, the STA and access points AP1-AP3 may be STA 210 andaccess points AP1-AP3, respectively, of FIG. 2A. For example, of themultiple access points AP1-AP3, only AP3 may be targeted by the STAduring a filtered scanning operation.

The STA initiates a filtered scanning operation by broadcasting atargeted probe request TPRQ at time t₀. As described above, the targetedprobe request TPRQ may include a custom IE (e.g., which may be a VSIEcontaining a MAC address of the STA) that may be used to filter incomingprobe responses. The available access points AP1-AP3 may respond to thetargeted probe request TPRQ by sending either a “standard” (e.g.,non-targeted) probe response or a targeted probe response TPRS back tothe STA.

For example, AP1 may send a standard probe response to the STA at timet₁. Because this probe request does not contain the STA's custom IE, itmay be filtered or ignored by the STA. At time t₂, AP3 sends a targetedprobe response TPRS to the STA. The targeted probe response TPRS mayinclude a custom IE that matches or mirrors the custom IE provided withthe targeted probe request TPRQ. Upon detecting a targeted proberesponse TPRS with the custom IE, the STA may terminate the scanningoperation and initiate authentication and association procedures withAP3 at time t₃.

In example embodiments, the STA may terminate the scanning operation inresponse to the first targeted probe response TPRS it receives (e.g.,even if other APs have not yet responded to the targeted probe requestTPRQ). For example, as shown in FIG. 3, the STA initiates anauthentication process with AP3, at time t₃, without waiting for AP2 tosend a probe response. Terminating the scanning operation as soon as theSTA receives a targeted probe response TPRS may significantly reduce thetime needed to establish a Wi-Fi connection with a target AP (e.g.,AP3). Moreover, because AP3 is the only target AP in this example, itwould not be advantageous for the STA to continue listening for proberesponses after receiving the targeted probe response TPRS from AP3(e.g., since any subsequent probe responses would not contain the customIE, and would therefore be filtered anyway).

To establish a Wi-Fi connection with the target AP (e.g., AP3), the STAsends an authentication request to AP3 at time t₃, and AP3 sends anauthentication response back to the STA at time t₄. The exchange ofauthentication information (e.g., from time t₃ to t₄) may correspondwith a low-level authentication process described by the IEEE 802.11specification. The STA then sends an association request to AP3 at timet₅, and AP3 sends an association response back to the STA at time t₆.During the association process (e.g., from time t₅ to t₆), the STA andAP3 negotiate one or more capabilities to be used for subsequentwireless communications. Once the devices are associated with oneanother, the STA and AP3 may perform a 4-way handshake, from time t₇ tot₈, to complete the connection process. For example, the STA and AP3 mayexchange EAPoL frames with one another to generate a PTK to be used forencrypting (and decrypting) data communicated between the two devices.

At time t₉ (and periodically thereafter), AP3 may broadcast a beaconframe containing the custom IE. The beacon frame may be used by AP3 toannounce its presence and to indicate to the STA that the Wi-Ficonnection is still “alive.” Additionally, the custom IE included in thebeacon frame may enable the STA to quickly identify AP3 during passivescanning operations. For example, the STA may passively scan thewireless channel (e.g., even while connected to AP3) by receiving beaconframes broadcast by APs operating on the channel. During conventionalpassive scanning operations, a STA may analyze all of the receivedbeacon frames and connect to any AP that provides a better connection(e.g., stronger RSSI value, greater bandwidth, better QoS, etc.) thanthe current AP. However, in example embodiments, the STA may filter anyincoming beacon frames that do not contain the custom IE (e.g., anybeacon frames not originating from AP3). This may reduce the time neededfor the STA to identify and reconnect to AP3 in the event that thedevices become disconnected.

FIG. 4 shows an example timing diagram 400 depicting a wirelessconnection operation with filtered re-scanning for APs. For purposes ofdiscussion herein, the STA and access points AP1-AP3 may be STA 210 andaccess points AP1-AP3, respectively, of FIG. 2A. For example, of themultiple access points AP1-AP3, only AP3 may be targeted by the STAduring a filtered scanning operation.

The STA initiates a filtered scanning operation by broadcasting atargeted probe request TPRQ at time t₀. As described above, the targetedprobe request TPRQ may include a custom IE (e.g., which may be a VSIEcontaining a MAC address of the STA) that may be used to filter incomingprobe responses. The available access points AP1-AP3 may respond to thetargeted probe request TPRQ by sending either a standard probe responseor a targeted probe response TPRS back to the STA. In exampleembodiments, the STA may initiate or activate a scan timer uponbroadcasting the targeted probe request TPRQ. For example, the scantimer may be used to limit the duration of the scanning operation.Moreover, the scan timer may reduce the overall duration of the scanningoperation by ensuring that the STA does not wait too long for a targetedprobe response TPRS before actively rescanning the wireless channel.

AP1 sends a standard probe response to the STA at time t₁. Because thisprobe response does not contain a custom IE that matches or mirrors thecustom IE in the targeted probe request TPRQ, AP1's probe response maybe filtered or ignored by the STA. AP2 sends a standard probe responseto the STA at time t₂. Because this probe response also does not containa matching custom IE, AP2's probe response may also be filtered orignored by the STA. In the example of FIG. 4, the STA may not receive aprobe response from AP3 before the scan timer expires, at time t₃. Forexample, AP3 may have failed to receive the targeted probe request TPRQsent by the STA, or the STA may have failed to receive a targeted proberesponse TPRS sent by AP3 (e.g., due to distance, interference, and/orother channel conditions).

When the scan timer expires, at time t₃, the STA determines that it hasnot yet received a targeted probe response TPRS (e.g., containing amatching custom IE) from any of the access points AP1-AP3. Accordingly,the STA may initiate another filtered scanning operation byre-broadcasting the targeted probe request TPRQ at time t₃. This time,AP1 responds with a standard probe response at time t₄, AP2 respondswith a standard probe response at time t₅, and AP3 responds with atargeted probe response TPRS that includes a matching custom IE at timet₆. Upon detecting the targeted probe response TPRS with the matchingcustom IE, the STA may terminate the scanning operation and initiateauthentication and association procedures with AP3 at time t₇.

To establish a Wi-Fi connection with the target AP (e.g., AP3), the STAsends an authentication request to AP3 at time t₇, and AP3 sends anauthentication response back to the STA at time t₈. Once authenticated,the STA sends an association request to AP3 at time t₉, and AP3 sends anassociation response back to the STA at time t₁₀. Finally, the devicesmay perform a 4-way handshake (not shown for simplicity) at time t₁₁ tocomplete the connection process.

FIG. 5 shows an example timing diagram 500 depicting a wirelessconnection operation with filtered AP selection. For purposes ofdiscussion herein, the STA and access points AP1-AP3 may be STA 210 andaccess points AP1-AP3, respectively, of FIG. 2B. For example, AP2 and/orAP3 may be targeted by the STA during a filtered scanning operation.

The STA initiates a filtered scanning operation by broadcasting atargeted probe request TPRQ at time t₀. As described above, the targetedprobe request TPRQ may include a custom IE (e.g., which may be a VSIEcontaining a MAC address of the STA) that may be used to filter incomingprobe responses. The available access points AP1-AP3 may respond to thetargeted probe request TPRQ by sending either a standard probe responseor a targeted probe response TPRS back to the STA. In exampleembodiments, the STA may initiate or activate a scan timer uponbroadcasting the targeted probe request TPRQ. For example, the scantimer may be used to limit the duration of the scanning operation whileensuring that the STA has sufficient time to receive a number oftargeted probe responses TPRSs (if available).

AP1 sends a standard probe response to the STA at time t₁. Because thisprobe response does not contain a custom IE that matches or mirrors thecustom IE in the targeted probe request TPRQ, AP1's probe response maybe filtered or ignored by the STA. AP3 sends a targeted probe responseTPRS with the matching custom IE to the STA at time t₂. Because thetargeted probe response TPRS contains the matching custom IE, the STAmay store information about AP3 (e.g., acquired from the targeted proberesponse TPRS) in a database of candidate APs. In example embodiments,the STA may continue listening for probe responses (e.g., until the scantimer expires) even after receiving the targeted probe response TPRSfrom AP3.

As described above, with respect to FIG. 2B, a WLAN may be formed bymultiple APs (e.g., such as AP2 and AP3). In some instances, the firstAP to send a targeted probe response TPRS to the STA may not provide thebest connection to the WLAN. Thus, it may be advantageous for the STA toreceive multiple targeted probe responses TPRSs (when available) andselect a target AP that provides the best connection to the WLAN.

For example, AP2 may also send a targeted probe response TPRS with thematching custom IE, at time t₃. Because the targeted probe response TPRScontains the matching custom IE, the STA may also store informationpertaining to AP2 (e.g., acquired from the targeted probe response TPRS)in a database of candidate APs. Thus, when the scan timer expires (e.g.,at time t₄), the STA may analyze the information for all of the APs inthe database of candidate APs and select a particular AP to connect to.In this example, AP2 may be closest in vicinity to the STA and maytherefore provide the highest signal strength (e.g., as indicated by anRSSI value). Accordingly, the STA may choose to establish a Wi-Ficonnection with AP2 (e.g., even though the STA first received a targetedprobe response TPRS from AP3).

To establish a Wi-Fi connection with the target AP (e.g., AP2), the STAsends an authentication request to AP2 at time t₄, and AP2 sends anauthentication response back to the STA at time t₅. Once authenticated,the STA sends an association request to AP2 at time t₆, and AP2 sends anassociation response back to the STA at time t₇. Finally, the STA andAP2 may perform a 4-way handshake, from time t₈ to t₉, to complete theconnection process.

At time t₁₀ (and periodically thereafter), AP2 may broadcast a beaconframe containing the custom IE. The beacon frame may be used to maintainthe Wi-Fi connection between the STA and AP2. As described above, thebeacon frame may also enable the STA to quickly identify and reconnectto AP2 in the event that the devices become disconnected. In exampleembodiments, any APs forming part of the WLAN to which the STA isconnected may subsequently broadcast beacon frames with the custom IE.For example, at time t₁₁ (and periodically thereafter), AP3 may alsobroadcast a beacon frame containing the custom IE. This allows the STAto quickly identify AP3 when passively scanning the wireless channel.Thus, if the STA subsequently moves out of wireless range with AP2,while remaining in range of AP3, the STA may remain connected to (e.g.,or quickly reconnect to) the WLAN by establishing a Wi-Fi connectionwith AP3.

FIG. 6 shows a STA 600 in accordance with example embodiments. STA 600may be one embodiment of STA 110 of FIG. 1. STA 600 includes at least atransceiver 610, a processor 620, and a memory 630. The transceiver 610may be used to communicate wirelessly with other suitable wirelessdevices (e.g., including wires access points and/or wireless stations).Processor 620, which is coupled to transceiver 610 and memory 630, maybe any suitable one or more processors capable of executing scripts orinstructions of one or more software programs stored in the STA 600(e.g., within memory 630). For purposes of discussion herein, processor620 is shown in FIG. 6 as being coupled between transceiver 610 andmemory 630. For actual embodiments, transceiver 610, processor 620,and/or memory 630 may be connected together using one or more buses (notshown for simplicity).

Memory 630 may include an AP database 632 that stores informationpertaining to a set of candidate APs. For example, the AP database 632may be updated each time the STA 600 receives a targeted probe response(e.g., with a custom IE) from a potential target AP. The AP database 632may be populated with information included in each targeted proberesponse. Memory 630 may also include a non-transitory computer-readablemedium (e.g., one or more non-volatile memory elements, such as EPROM,EEPROM, Flash memory, a hard drive, etc.) that may store the followingsoftware modules:

-   -   a filtered scanning module 634 to scan a wireless channel using        a custom IE to identify a set of candidate APs;    -   a response filtering module 636 to selectively filter incoming        probe responses based at least in part on whether the probe        responses contain the custom IE; and    -   an AP selection module 638 to select a target AP to connect to        from the set of candidate APs.        Each software module includes instructions that, when executed        by processor 620, causes the STA 600 to perform the        corresponding functions. The non-transitory computer-readable        medium of memory 630 thus includes instructions for performing        all or a portion of the operations described below with respect        to FIGS. 8 and 9.

For example, processor 620 may execute the filtered scanning module 634to scan a wireless channel using a custom IE to identify a set ofcandidate APs. Processor 620 may also execute the response filteringmodule 636 to selectively filter incoming probe responses based at leastin part on whether the probe responses contain the custom IE. Further,processor 620 may execute the AP selection module 638 to select a targetAP to connect to from the set of candidate APs.

FIG. 7 shows an AP 700 in accordance with example embodiments. AP 700may be one embodiment of AP 120 of FIG. 1. AP 700 includes at least atransceiver 710, a processor 720, and a memory 730. The transceiver 710may be used to communicate wirelessly with other suitable wirelessdevices (e.g., including wireless access points and/or wirelessstations). Processor 720, which is coupled to transceiver 710 and memory730, may be any suitable one or more processors capable of executingscripts or instructions of one or more software programs stored in theAP 700 (e.g., within memory 730). For purposes of discussion herein,processor 720 is shown in FIG. 7 as being coupled between transceiver710 and memory 730. For actual embodiments, transceiver 710, processor720, and/or memory 730 may be connected together using one or more buses(not shown for simplicity).

Memory 730 may include a custom IE store 732 that stores informationcontained in a custom IE of a targeted probe request received from aSTA. For example, upon receiving a targeted probe request, the AP 700may parse the information included in the custom IE field and store theinformation in the custom IE store 732. Memory 730 may also include anon-transitory computer-readable medium (e.g., one or more non-volatilememory elements, such as EPROM, EEPROM, Flash memory, a hard drive,etc.) that may store the following software modules:

-   -   a request filtering module 734 to filter incoming probe requests        that do not contain a custom IE;    -   a probe synchronization module 736 to generate a targeted probe        response with a custom IE that matches or mirrors the custom IE        of a received targeted probe request; and    -   a beacon synchronization module 738 to generate beacon frames        containing the custom IE.        Each software module includes instructions that, when executed        by processor 720, causes the AP 700 to perform the corresponding        functions. The non-transitory computer-readable medium of memory        730 thus includes instructions for performing all or a portion        of the operations described below with respect to FIG. 10.

For example, processor 720 may execute the request filtering module 734to filter incoming probe requests that do not contain a custom IE.Processor 720 may also execute the probe synchronization module 736 togenerate a targeted probe response with a custom IE that matches ormirrors the custom IE of a received targeted probe request. Further,processor 720 may execute the beacon synchronization module 738 togenerate beacon frames containing the custom IE.

FIG. 8 shows a flowchart depicting an example filtered scanningoperation 800. With reference, for example, to FIG. 1, the exampleoperation 800 may be performed by the STA 110 to identify and connect toa target AP (e.g., AP 120). The STA 110 initiates the filtered scanningoperation 800 by broadcasting a probe request 101 with a custom IE(810). For example, the custom IE may be a VSIE containing informationthat is unique to the STA 110 (e.g., such as a MAC address of the STA110). The STA 110 then receives probe responses from one or more APs inthe vicinity (820). For example, each AP that receives the probe requestmay send a probe response back to the STA that mirrors the informationprovided in the probe request intersected with the capabilitiessupported by that AP.

The STA 110 may identify the target AP (e.g., AP 120) from the one ormore received probe responses, based at least in part on whether theprone responses contain the custom IE. In example embodiments, thetarget AP 120 sends a probe response 102 that includes a custom IEmatching or mirroring the custom IE included in the probe request. Incontrast, other APs may send standard probe responses (e.g., that do notcontain the custom IE) back to the STA 110. This allows the STA 110 toquickly distinguish probe responses originating from the AP 120 fromother incoming probe responses. In example embodiments, the STA 110 mayfilter any incoming probe responses that do not contain the custom IE(e.g., to further reduce the overhead necessary to complete the filteredscanning operation 800).

Once the STA 110 has identified (and selected) the target AP, the STA110 may proceed to establish a Wi-Fi connection with the target AP(840). For example, the STA 110 may authenticate to the AP 120 bysending an authentication request 103 to, and receiving anauthentication response 104 back from, the AP 120. The STA 110 may thenassociate to the AP 120 by sending an association request 105 to, andreceiving an association response 106 back from, the AP 120. Finally,the STA 110 and AP 120 may complete the connection process by performinga 4-way handshake 108 (e.g., by exchanging EAPoL frames between thedevices).

FIG. 9 shows a flowchart depicting a more detailed example of a filteredscanning operation 900. With reference, for example, to FIG. 6, theoperation 900 may be performed by the STA 600 to identify a set ofcandidate APs, and to select a target AP to connect to from the set ofcandidate APs.

The STA 600 initiates the filtered scanning operation 900 bybroadcasting a targeted probe request with a custom IE on apredetermined channel (910). For example, the processor 620 may executethe filtered scanning module 634 to generate the targeted probe requestby writing a unique set of information (e.g., such as the MAC address ofthe STA 600) in the VSIE field of an outgoing probe request. In exampleembodiments, the processor 620, in executing the filtered scanningmodule 634, may cause transceiver 610 to broadcast the targeted proberequest on a predetermined channel (e.g., the channel that the target APis expected to reside on).

The STA 600 may initiate a scan timer upon broadcasting the targetedprobe request (920). For example, the filtered scanning module 634, asexecuted by the processor 620, may cause the STA 600 to continuallylisten for probe responses for a given duration (e.g., until expirationof the scan timer). The scan timer may be configured to limit the amountof time the STA 600 listens for probe responses before attempting tore-scan the wireless channel (e.g., if no targeted probe response isreceived before expiration of the scan timer). Additionally, and/oralternatively, the scan timer may be configured to ensure that the STA600 continues listening for probe responses for a duration long enoughto ensure that the STA 600 receives a targeted probe response from anyavailable (and capable) AP within wireless range of the STA 600.

Upon receiving a probe response (930), the STA 600 may first determinewhether the probe response includes a custom IE (940). For example, theprocessor 620 may execute the response filtering module 636 to comparethe information contained in the VSIE field (if available) of theincoming probe response with the information contained in the VSIE fieldof the targeted probe request. If the VSIE field of the incoming proberesponse does not match the VSIE field of the targeted probe request(e.g., the custom IE is not detected), the STA 600 may filter the proberesponse (945). Specifically, the processor 620, in executing theresponse filtering module 636, may ignore the incoming probe response,thus ensuring that the AP that sent the probe response is not availablefor consideration during a subsequent AP selection process. In exampleembodiments, the probe response filtering may be performed in firmware.

If the STA 600 detects a custom IE in the probe response that matches ormirrors the custom IE of the targeted probe request, the STA 600 maystore information pertaining to the corresponding AP in a database ofcandidate APs (950). For example, the processor 620, in executing theresponse filtering module 636, may store the received probe response(e.g., and/or information provided therewith) in the AP database 632.This process of receiving and selectively storing incoming proberesponses (930-960) may be repeated for as long as the scan timer hasnot yet expired (960).

Once the scan timer expires, the STA 600 may determine whether anycandidate APs have been detected (970). For example, the processor 620may execute the AP selection module 638 to determine whether the APdatabase 632 contains stored information from one or more received proberesponses (e.g., targeted probe responses). If no candidate APs aredetected, the STA 600 may re-broadcast the targeted probe request (910)to initiate another scanning operation 900. However, if the STA 600identifies at least one candidate AP, the STA 600 may then select aparticular AP from the set of candidate APs as the target AP (980). Forexample, the processor 620, in executing the AP selection module 638,may select an AP from the AP database 632 that is best suited to theneeds of the STA 600 (e.g., such as the AP with the highest signalstrength).

Finally, the STA 600 may proceed to establish a Wi-Fi connection withthe target STA (990). As described above, the STA 600 may firstauthenticate to the target AP by sending an authentication request to,and receiving an authentication response back from, the target AP. TheSTA 600 may then associate to the target AP by sending an associationrequest to, and receiving an association response back from, the targetAP. The STA 600 may then complete the connection process by performing a4-way handshake (e.g., by exchanging EAPoL frames) with the target AP.

FIG. 10 shows a flowchart depicting an operation 1000 of an AP inaccordance with example embodiments. With reference, for example, toFIG. 7, the operation 1000 may be performed by the AP 700 to establish aWi-Fi connection with a particular STA and/or with a particular type ofwireless device.

The AP 700 receives an incoming probe request (1010) and determineswhether the probe request includes a custom IE (1020). For example, theprocessor 720 may execute the request filtering module 734 to analyzethe information contained in the VSIE field (if available) of theincoming probe request. The request filtering module 734, as executed bythe processor 720, may parse the VSIE field for information that isunique to the requesting STA (e.g., such as a MAC address of the STA)and/or other information indicating that the AP 700 is an intendedtarget of a filtered scanning operation (e.g., as described above withrespect to FIG. 9). If the VSIE field is empty and/or is not indicativeof a custom IE, the AP 700 may filter the probe request (1025).Specifically, the processor 720, in executing the request filteringmodule 734, may ignore the incoming probe request (e.g., withoutanalyzing any additional information included in the probe request) andrefrain from sending a probe response back to the requesting STA. Inexample embodiments, the probe request filtering may be performed infirmware.

If the AP 700 detects a custom IE in the probe request, the AP 700 maystore information provided within the custom IE in a custom IE database(1030). For example, the processor 720, in executing the requestfiltering module 734, may store the received probe request (e.g., and/orinformation provided in the VSIE field of the probe request) in thecustom IE store 732. The AP 700 then sends a targeted probe responsewith a matching custom IE back to the requesting STA (1040). Forexample, the processor 720 may execute the probe synchronization module736 to generate a probe response with a VSIE field containinginformation that matches or mirrors the information contained in theVSIE field of the received probe request (e.g., as stored in the customIE store 732).

After sending the targeted probe response, the AP 700 listens for anauthentication request from the requesting STA (1050). If the AP 700receives an authentication request, the AP 700 may proceed to establisha Wi-Fi connection with the corresponding STA (1055). For example, theAP 700 may respond to the authentication request by sending anauthentication response back to the STA. The AP 700 may then receive anassociation request and send an association response back to the STA.Finally, the AP 700 may complete the connection process by performing a4-way handshake (e.g., by exchanging EAPoL frames) with the STA.

Once the AP 700 is connected to the requesting STA, the AP 700 maysubsequently (and periodically) broadcast beacon frames with the STA'scustom IE (1060). For example, the processor 720 may execute the beaconsynchronization module 738 to generate beacon frames with a VSIE fieldcontaining information that matches or mirrors the information containedin the VSIE field of the received probe request (e.g., as stored in thecustom IE store 732). For example, the custom IE included in the beaconframe may enable the STA to identify the AP 700 during passive scanningoperations. For example, the beacon frames may enable the STA tomaintain a Wi-Fi connection with the AP 700, and to quickly reconnect tothe AP 700 in the event that the devices become disconnected.

In example embodiments, the AP 700 may generate beacon frames thatinclude the custom IE even if the AP 700 does not establish a Wi-Ficonnection with the requesting STA. As described above, this may enablethe STA to quickly identify the AP 700 (e.g., through passive scanning)and to establish a Wi-Fi connection with the AP 700 if (and when)needed.

In the foregoing specification embodiments have been described withreference to specific examples. It will, however, be evident thatvarious modifications and changes may be made thereto without departingfrom the broader scope of the disclosure as set forth in the appendedclaims. For example, the method steps depicted in the flow charts ofFIGS. 8-10 may be performed in other suitable orders, multiple steps maybe combined into a single step, and/or some steps may be omitted (orfurther steps included). The specification and drawings are,accordingly, to be regarded in an illustrative sense rather than arestrictive sense.

What is claimed is:
 1. A method of connecting a wireless station (STA)to an access point (AP), the method being performed by the STA andcomprising: broadcasting a probe request that includes a custominformation element (IE); receiving probe responses from one or more APsin response to the probe request; identifying a target AP based at leastin part on whether one or more of the received probe responses includethe custom IE; and connecting to the target AP.
 2. The method of claim1, wherein the custom IE is a vendor-specific IE including a mediaaccess control (MAC) address of the target AP.
 3. The method of claim 1,wherein broadcasting the probe request comprises: broadcasting the proberequest only on a predetermined channel associated with the target AP.4. The method of claim 1, wherein the target AP is to respond to theprobe request by sending a probe response that includes the custom IE.5. The method of claim 1, wherein identifying the target AP comprises:identifying a set of candidate APs based on one or more of the receivedprobe responses that include the custom IE; and selecting the target APfrom the set of candidate APs.
 6. The method of claim 1, furthercomprising: initiating a timer upon broadcasting the probe request; andin response to none of the received probe responses include the customIE upon expiration of the timer, rebroadcasting the probe request withthe custom IE.
 7. The method of claim 1, further comprising: ignoringany probe responses that do not include the custom IE.
 8. The method ofclaim 1, further comprising: receiving a beacon frame from the targetAP, wherein the beacon frame includes the custom IE; and identifying thetarget AP based at least in part on the received beacon frame.
 9. Acommunications device, comprising: a memory element storing instructionsfor connecting to an access point (AP); and one or more processors that,upon executing the instructions, cause the communications device to:broadcast a probe request that includes a custom information element(IE); receive probe responses from one or more APs in response to theprobe request; identify a target AP based at least in part on whetherone or more of the received probe responses include the custom IE; andconnect to the target AP.
 10. The communications device of claim 9,wherein the custom IE is a vendor-specific IE including a media accesscontrol (MAC) address of the target AP.
 11. The communications device ofclaim 9, wherein execution of the instructions to broadcast the proberequest causes the communications device to: broadcast the probe requestonly on a predetermined channel associated with the target AP.
 12. Thecommunications device of claim 9, wherein the target AP is to respond tothe probe request by sending a probe response that includes the customIE.
 13. The communications device of claim 9, wherein execution of theinstructions to identify the target AP further causes the communicationsdevice to: identify a set of candidate APs based on one or more of thereceived probe responses that include the custom IE; and select thetarget AP from the set of candidate APs.
 14. The communications deviceof claim 9, wherein execution of the instructions further causes thecommunications device to: initiate a timer upon broadcasting the proberequest; and in response to none of the received probe responses includethe custom IE upon expiration of the timer, rebroadcast the proberequest with the custom IE.
 15. The communications device of claim 9,wherein execution of the instructions further causes the communicationsdevice to: ignore any probe responses that do not include the custom IE.16. The communications device of claim 9, wherein execution of theinstructions further causes the communications device to: receive abeacon frame from the target AP, wherein the beacon frame includes thecustom IE; and identify the target AP based at least in part on thereceived beacon frame.
 17. A communications device, comprising: meansfor broadcasting a probe request that includes a custom informationelement (IE); means for receiving probe responses from one or moreaccess points (APs) in response to the probe request; means foridentifying a target AP based at least in part on whether one or more ofthe received probe responses include the custom IE; and means forconnecting to the target AP.
 18. The communications device of claim 17,wherein the custom IE is a vendor-specific IE including a media accesscontrol (MAC) address of the target AP.
 19. The communications device ofclaim 17, wherein the means for broadcasting the probe request is to:broadcast the probe request only on a predetermined channel associatedwith the target AP.
 20. The communications device of claim 17, whereinthe target AP is to respond to the probe request by sending a proberesponse that includes the custom IE.
 21. The communications device ofclaim 17, wherein the means for identifying the target AP is to:identify a set of candidate APs based on one or more received proberesponses that include the custom IE; and select the target AP from theset of candidate APs.
 22. The communications device of claim 17, furthercomprising: means for initiating a timer upon broadcasting the proberequest; and means for rebroadcasting the probe request with the customIE in response to none of the received probe responses include thecustom IE upon expiration of the timer.
 23. The communications device ofclaim 17, further comprising: means for ignoring any probe responsesthat do not include the custom IE.
 24. The communications device ofclaim 17, further comprising: means for receiving a beacon frame fromthe target AP, wherein the beacon frame includes the custom IE; andmeans for identifying the target AP based at least in part on thereceived beacon frame.
 25. A non-transitory computer-readable storagemedium containing program instructions that, when executed by aprocessor of a communications device, causes the communications deviceto: broadcast a probe request that includes a custom information element(IE); receive probe responses from one or more access points (APs) inresponse to the probe request; identify a target AP based at least inpart on whether one or more of the received probe responses include thecustom IE; and connect to the target AP.
 26. The non-transitorycomputer-readable storage medium of claim 25, wherein the custom IE is avendor-specific IE including a media access control (MAC) address of thetarget AP.
 27. The non-transitory computer-readable storage medium ofclaim 25, wherein execution of the instructions to broadcast the proberequest causes the communications device to: broadcast the probe requestonly on a predetermined channel associated with the target AP.
 28. Thenon-transitory computer-readable storage medium of claim 25, whereinexecution of the instructions to identify the target AP causes thecommunications device to: identify a set of candidate APs based on oneor more of the received probe responses that include the custom IE; andselect the target AP from the set of candidate APs.
 29. Thenon-transitory computer-readable storage medium of claim 25, whereinexecution of the instructions further causes the communications deviceto: initiate a timer upon broadcasting the probe request; and inresponse to none of the received probe responses include the custom IEupon expiration of the timer, rebroadcast the probe request with thecustom IE.
 30. The non-transitory computer-readable storage medium ofclaim 25, wherein execution of the instructions further causes thecommunications device to: ignore any probe responses that do not includethe custom IE.